/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.nacos.plugin.datasource.enums;

import java.util.HashMap;
import java.util.Map;

/**
 * The TrustedSqlFunctionEnum enum class is used to enumerate and manage a list of trusted
 * built-in SQL functions. By using this enum, you can verify whether a given SQL function
 * is part of the trusted functions list to avoid potential SQL injection risks.
 *
 * @author blake.qiu
 * @author laokou
 */
public enum TrustedPostgresqlFunctionEnum {

	/**
	 * NOW().
	 */
	NOW("NOW()", "CURRENT_TIMESTAMP(3)");

	private static final Map<String, TrustedPostgresqlFunctionEnum> LOOKUP_MAP = new HashMap<>();

	static {
		for (TrustedPostgresqlFunctionEnum entry : TrustedPostgresqlFunctionEnum.values()) {
			LOOKUP_MAP.put(entry.functionName, entry);
		}
	}

	private final String functionName;

	private final String function;

	TrustedPostgresqlFunctionEnum(String functionName, String function) {
		this.functionName = functionName;
		this.function = function;
	}

	/**
	 * Get the function name.
	 * @param functionName function name
	 * @return function
	 */
	public static String getFunctionByName(String functionName) {
		TrustedPostgresqlFunctionEnum entry = LOOKUP_MAP.get(functionName);
		if (entry != null) {
			return entry.function;
		}
		throw new IllegalArgumentException(String.format("Invalid function name: %s", functionName));
	}

}
